Question 1

How is eval (evaluation) measured?

Accepted Answer

Eval is always shown from White's perspective. A positive number (+1.5) means White is better by roughly 1.5 pawns. A negative number (−1.5) means Black is better. This is the chess convention Stockfish uses, regardless of which color you played.

Question 2

What is the difference between Review Games and Analysis Board?

Accepted Answer

Review Games imports your games from Chess.com or Lichess (or via PGN) and runs a full analysis pass, classifying every move. Analysis Board is a free-play board where you set up any position and explore lines interactively with Stockfish. Use Review Games to study what happened; use Analysis Board to explore what could have happened.

Question 3

What does 'continuous analysis' do?

Accepted Answer

When continuous analysis is on, Stockfish keeps running in the background as you step through moves, updating the eval and best lines in real time. When it's off, analysis only runs when you explicitly request it. Continuous analysis is more useful for deep study; turning it off saves battery on mobile.

Question 4

What is PV (Principal Variation)?

Accepted Answer

PV stands for Principal Variation—the sequence of best moves Stockfish calculates from the current position. It shows you not just the top move, but the full line it expects to follow. You can step through the PV in the analysis panel to see how the engine expects play to continue.

Question 5

Why do move labels and arrows change as I step through the game?

Accepted Answer

Move labels (Best, Excellent, Blunder, etc.) are calculated relative to the position before each move. As you step forward or backward, the board position changes, so Stockfish recalculates from that point. Arrows show the engine's preferred move from the current position—they update as the position changes.

Question 6

What depth should I use?

Accepted Answer

Balanced (depth 18) is the best default for everyday game review—fast enough to analyze many games without being slow, accurate enough to catch real mistakes. Deep (24) is good for games you want to study seriously. Ultra (35) and Mega (50) are for positions where you want maximum precision and don't mind waiting.

Question 7

What is the difference between cache, archive, and clearing Your Data?

Accepted Answer

Cache is the browser's stored copy of the app and Stockfish engine (for offline use)—clearing it means re-downloading everything on your next visit. Archive is your saved analyses stored in your browser's local storage—clearing it deletes your game history. Your Data page lets you manage both independently.

Question 8

Are Legends and Pros paid tiers?

Accepted Answer

No. Legends and Pros are curated collections of classic games and well-known players available for everyone to analyze. They are not subscription tiers or premium features.

Question 9

Does Chessomy support Chess960 and other chess variants?

Accepted Answer

Yes. Chessomy fully supports Chess960 (Fischer Random Chess) and Casablanca Chess. Stockfish 18 analyzes all variant positions with the same depth and accuracy as standard games. Import a variant PGN or set up the position on the Analysis Board and the engine handles it natively.

Frequently asked questions

Understanding Analysis

Features

Settings & Performance

Your Data

Frequently asked questions

Understanding Analysis

How is eval (evaluation) measured?

What is PV (Principal Variation)?

Why do move labels and arrows change as I step through a game?

What does 'continuous analysis' do?

What is "#M nodes explored" on the loading bar?

What do values like 57.1, D24, ~12 moves, and 1.5M/s mean?

Why are both players at 0% accuracy?

What are the arrows on the board?

Features

What's the difference between Review Games and Analysis Board?

Are Legends and Pros paid tiers?

How are blunder puzzles generated?

Settings & Performance

What depth should I use?

Will Chessomy drain my battery?

Why is analysis slower on some devices?

Does Chessomy support Chess960 and other variants?

Your Data

What's the difference between cache, archive, and clearing Your Data?

How do I export my games? What's the difference between PGN and JSON backup?

Is my data backed up anywhere?

Will cloud sync require an account?